Critical severity · published Oct 20, 2026
CVE-2026-101356
Apache Tomcat: HTTP/2 request/response mix-up after error during async processing
9.1
CVSS
0.5%
EPSS
No
On KEV
Description
Incorrect object recycling and re-use vulnerability in Apache Tomcat affecting HTTP/2 processing of asynchronous servlets can trigger request and/or response mix-up between users.
This issue affects Apache Tomcat: from 11.0.22 through 11.0.26, from 10.1.55 through 10.1.60, from 9.0.118 through 9.0.122.
Users are recommended to upgrade to version 11.0.27, 10.1.61 or 9.0.123, which fixes the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.5% · higher than 43% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
Tomcat · Apache
11.0.22 through 11.0.26; 10.1.55 through 10.1.60; 9.0.118 through 9.0.122 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-101356
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-101356
lists.apache.org
https://lists.apache.org/thread.html/d1xjt7bbjqw7y7n5mcb4fm815hpfgc27
www.openwall.com
http://www.openwall.com/lists/oss-security/2026/10/20/27
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